shapely is_valid for polygons in 3D
gis, python, shapely
Solution
The problem is that `shapely` in fact ignores the z coordinate. So, as far as shapely can tell you are building a polygon with the points `[(1,0),(1,1), (1,1)]` that aren't enough to build a polygon.
See this other SO question for more information: python-polygon-does-not-close-shapely.
IMHO, shapely shouldn't allow three dimension coordinates, because it brings this kind of confusions.
Problem
I'm trying to validate some polygons that are on planes with `is_valid`, but I get `Too few points in geometry component at or near point` for polygons where the z is not constant. Is there a way to validate these other polygons? Here's an example: ``` from shapely.geometry import Polygon poly1 = Polygon([(0,0), (1,1), (1,0)]) print(poly1.is_valid) # True # z=1 poly2 = Polygon([(0,0,1), (1,1,1), (1,0,1)]) print(poly2.is_valid) # True # x=1 poly3 = Polygon([(1,0,0), (1,1,1), (1,1,0)]) print(poly3.is_valid) # Too few points in geometry component at or near point 1 0 0 # False ```